About This Page
This is a clinician-written, evidence-based summary aligned to the 2026 MLA Content Map. It is intended for medical students and junior doctors preparing for the UKMLA. Always cross-reference with NICE guidance, local protocols, and clinical judgement.
Key points
- LARC methods are most effective: IUD (>99%), IUS (>99%), implant (>99%), injection (>99%). Promote LARC first-line (NICE)
- COCP: contains oestrogen + progestogen. Contraindicated in migraine with aura, BMI >35 + age >35 + smoking, active VTE, breast cancer
- POP (desogestrel/norethisterone): no oestrogen — safer with migraine, VTE risk. Desogestrel inhibits ovulation; 12-hour missed pill window
- Cu-IUD: most effective emergency contraception (within 5 days). Also used as ongoing LARC for up to 10 years
- Emergency contraception: levonorgestrel 1.5 mg (within 72 h), ulipristal 30 mg (within 120 h), Cu-IUD (within 120 h — most effective)
- UKMEC categories: 1 = unrestricted, 2 = benefits outweigh risks, 3 = risks outweigh benefits, 4 = unacceptable risk
Overview
Contraception encompasses all methods used to prevent pregnancy. Methods range from natural family planning and barrier methods (condoms, diaphragm) to hormonal contraception (COCP, POP, patch, ring, injection, implant, IUS) and non-hormonal intrauterine devices (Cu-IUD). NICE recommends that long-acting reversible contraception (LARC) should be discussed and offered to all women as first-line, as these methods have the highest efficacy due to elimination of user-dependent factors. Choice of method should be based on individual preference, medical eligibility (UKMEC criteria), and lifestyle factors. The Faculty of Sexual and Reproductive Healthcare (FSRH) provides UK-specific clinical guidelines.
Epidemiology
Approximately 75% of women of reproductive age in the UK use some form of contraception. The most commonly used methods are the COCP (~25%), male condoms (~25%), IUS (~10%), and implant (~8%). Despite availability, unintended pregnancy rates remain significant — approximately 45% of pregnancies in the UK are unplanned. Emergency contraception is used by approximately 5% of women per year. LARC use has been increasing but remains underutilised relative to its efficacy.
Clinical Features
Symptoms
Contraceptive counselling involves assessing current method use, satisfaction, and medical eligibility
Signs
BP measurement before starting COCP (oestrogen increases BP)
BMI assessment — COCP less effective and higher risk if BMI >35
Investigations
First-line
Blood pressureRequired before starting COCP (oestrogen-containing). Raised BP (≥140/90) is UKMEC 3 for COCP
Pregnancy testIf any possibility of pregnancy before starting or switching methods
BMIRelevant for COCP eligibility and injection (Depo-Provera affects bone density in <18 and >45)
Second-line
STI screeningOffer opportunistic chlamydia/gonorrhoea screening, especially if <25 or new IUD/IUS insertion
Specialist
Specialist referralIf complex medical history, UKMEC 3/4, or insertion difficulties with IUD/IUS
1
Long-acting reversible contraception (LARC) — most effective
- Copper IUD (Cu-IUD): non-hormonal, lasts 5–10 years, >99% effective. May increase menstrual bleeding/pain. Most effective emergency contraception
- Levonorgestrel IUS (LNG-IUS): e.g., Mirena (52 mg, 5 years). Reduces menstrual bleeding. Also treats HMB and provides endometrial protection in HRT. >99% effective
- Subdermal implant (etonogestrel — Nexplanon): lasts 3 years, >99% effective. Common side effect: irregular bleeding. Inserted in upper arm
- Injectable (DMPA — Depo-Provera): medroxyprogesterone acetate 150 mg IM every 12 weeks. >99% effective. Delays return to fertility. Bone density concerns in young (<18) and older (>45) women — limit to 2 years
2
Combined hormonal contraception (CHC)
- COCP: oestrogen (ethinylestradiol) + progestogen. >99% effective with perfect use, ~91% with typical use
- Combined patch (Evra): weekly change for 3 weeks + 1 patch-free week
- Combined vaginal ring (NuvaRing): in situ 3 weeks, out 1 week
- Contraindications (UKMEC 4): migraine with aura, active/history of VTE/PE, breast cancer, severe liver disease, uncontrolled hypertension, age ≥35 + smoking ≥15/day
- Benefits beyond contraception: reduces acne, HMB, dysmenorrhoea, ovarian and endometrial cancer risk
3
Progestogen-only methods
- POP (desogestrel 75 mcg — Cerazette/generics): inhibits ovulation. 12-hour missed pill window. No oestrogen — safe with migraine with aura, VTE risk
- Older POPs (norethisterone): primarily thicken cervical mucus. Only 3-hour missed pill window — largely superseded by desogestrel
- Safe in breastfeeding from immediately postpartum
4
Emergency contraception
- Cu-IUD: most effective. Insert within 120 hours (5 days) of UPSI. Can also be retained as ongoing contraception
- Ulipristal acetate (ellaOne) 30 mg oral: within 120 hours. More effective than levonorgestrel. Cannot use if already on hormonal contraception (progesterone receptor modulator — interaction)
- Levonorgestrel 1.5 mg (Levonelle) oral: within 72 hours (3 days). Less effective than ulipristal. Efficacy decreases with time
- Cu-IUD is first-line if within timeframe and acceptable to the woman
5
Postpartum contraception
- LARC: can fit Cu-IUD or IUS within 48 hours of delivery, or defer to 4+ weeks
- POP and implant: safe from immediately postpartum, including breastfeeding
- COCP: avoid until 6 weeks postpartum (VTE risk). 3 weeks if not breastfeeding and no additional VTE risk factors
- Breastfeeding provides some contraceptive effect (lactational amenorrhoea method) but only if fully breastfeeding, <6 months postpartum, and amenorrhoeic
Complications
- COCP — VTE: 2–4x increased risk (absolute risk still low ~5–12 per 10,000 women-years). Higher with 3rd/4th generation progestogens (gestodene, desogestrel, drospirenone)
- COCP — stroke: Increased risk in women with migraine with aura — ABSOLUTE contraindication (UKMEC 4)
- IUD/IUS — perforation: ~1–2 per 1,000 insertions. Risk higher with recent delivery or breastfeeding
- IUD/IUS — expulsion: ~5% in first year. More common with heavy periods or recent insertion
- Depo-Provera — bone density: Reversible decrease in BMD. Caution in adolescents and perimenopausal women
- Implant — irregular bleeding: Most common reason for early removal
UKMLA Exam Tips
- 1UKMEC 4 for COCP: migraine WITH AURA, active VTE, breast cancer, uncontrolled HTN, smoker ≥35 + ≥15 cigs/day
- 2Migraine without aura = UKMEC 2 for COCP (can use). WITH aura = UKMEC 4 (absolute contraindication)
- 3Cu-IUD = most effective emergency contraception AND non-hormonal long-term option
- 4Ulipristal (ellaOne): within 120 h, more effective than levonorgestrel. Cannot use alongside hormonal contraception
- 5POP (desogestrel): 12-hour missed pill window. Safe with migraine with aura and VTE risk
- 6COCP reduces risk of ovarian and endometrial cancer — commonly tested benefit
- 7Postpartum: POP/implant safe immediately. COCP not until ≥3–6 weeks (VTE risk)
- 8Depo-Provera delays return to fertility (up to 12 months after last injection)
Put your reading into practice
Topic-specific question practice is not linked for this article yet.
Choose UKMLA questions from the existing bank. General exam practice covers your selected topics; it is not filtered to this article. Your usual question-bank access applies.
Choose UKMLA practiceAfter your session, return to this section to revisit the reading and choose your next review.
Verified Sources & References
related resources
Save your place and choose what comes next
Obstetrics & Gynaecology · Article 30 of 31